Multiplexed identical broad-band-chirped grating interrogation system for large-strain sensing applications

We report here a simple and low-cost technique for extreme strain measurement, The overlapping of a chirped sensor grating with an identical reference de,ice provides a novel mechanism for measuring strain, This system permits a linear relationship between strain and resultant optical power, The maximum sensing range of the system is determined by the bandwidths of the gratings employed, A 20-nm chirped grating facilitates a sensing range up to 20000 mu epsilon. This paper also demonstrates an arrangement for multiplexing up to four gratings, which can be rapidly and truly simultaneously interrogated.